By definition, these diseases occur on plants only until about one or two weeks after seedling emergence. Seed diseases are caused by fungi which may be on the seed at planting or by fungi in the soil. They are often responsible for poor emergence and thin stands. Seedling diseases occur after germination until shortly after emergence. If the disease occurs before emergence, the seedling may rot before it has a chance to get out of the soil. This is referred to as preemergence damping-off. After emergence, seedling stems may be attacked at or below the soil line in what is termed postemergence damping-off. There are two general symptoms which occur at this time, brown to reddish-brown or black cankers at the soil line and a soft watery rot. In the first instance, if the cankers girdle the stem, the seedling falls over and dies; or, with partial girdling, the plant may continue to live, but will be stunted. In the second instance, the soft watery rot continues until the entire seedling decays. Seed and seedling diseases are most common in cool, wet soils. They are controlled by planting crops in warm soil, by fungicide seed treatments and by use of in-furrow, broadcast, or band-applied fungicides.